(1) Field of the Invention
This invention relates to the shelling of pecans. Operators of pecan shelling operations have ordinary skill in this art.
(2) Description of the Related Art
The state of the art for mass mechanical shelling of pecans comprises many steps. Pecans are initially harvested from an individual orchard and delivered to a pecan shelling facility.
A pecan shelling facility is schematically shown in FIG. 7. Normally the pecans from an orchard will be of a single variety. At the pecan shelling facility, the pecans are first separated by a sizer 80. Sizing pecans from an orchard involves separating by thickness. Since the ratio of a pecan's thickness to its length and width is substantially constant for a particular pecan variety, separating by thickness is sufficient to group pecans of substantially the same thickness, width, and length. Pecan sizes are numbered in accordance with their thickness in sixteenths of an inch, e.g. a group of pecans with a thickness of 13/16" are size 13 pecans.
The next step in the shelling process involves feeding pecans of a particular size to a cracker 82. Having the pecans separated by sizes allows for optimal performance of the cracker.
After the pecans are cracked according to standard practice before this invention, everything that comes out of the cracker is called cracker product 84. The cracker product (including whole uncracked pecans) is fed to a plant sheller 86. The sheller, as the name implies, further releases or frees any of the woody outer shell from the meat product therein.
The output of the sheller is then fed to a series of screens 88. The screens separate the sheller product by width, and each width range is fed individually to air separators. In the air separation process, meat from the pecan is separated from any of the woody shell by operation of the lighter shell pieces moving with air.
The meat is separated into different batches for use. In order of value, these will be halves, extra large pieces, large pieces, medium, and smalls and midgets. The air separator will generally be identified as halve separator 90, extra large separator 92, large separator 94, and medium, small, and midget separator units 96.
As described above, the sized pecans are fed to a cracker. When pecans leave the cracker, 25%-50% of the total possible meats halves are completely separated from the shells. When a portion of the shell remains attached to the meat it is referred to as a "sticktight". When the meat is entirely free from the shell it is referred to as "sticktight free"; therefore, after cracking, 25%-50% of the meat from the pecans will be sticktight free. According to present practice all of the cracked pecans, even those that are sticktight free, are fed to the sheller. The sheller's main purpose is to remove the woody shell portion from sticktights; therefore, feeding the sticktight free meat halves to the sheller often breaks the sticktight free meat halves and other meat portions thereby reducing their value.